DE3303742C2 - Process for the region-specific partial hydrogenation of anthracene or its derivatives - Google Patents

Abstract

Process for the region-specific partial hydrogenation of polynuclear aromatics with an anthracene base. Polynuclear aromatic compounds that have an anthracene base can be hydrogenated region-specifically on a terminal ring by homogeneously catalyzed hydrogen transfer from a secondary alcohol to the polynuclear aromatic compound, using a solution of a hydridoruthenium complex of the general formula $ A Hx Ru (P R3 ) y or Hx Ru [P (OR) 3] y $ A $ A where x = 2 and y = 4 or x = 4 and y = 3 and R is an aryl or alkyl group, used in an inert organic solvent will.

Description

of 55% of the anthracene. If the excess of secondary alcohols is increased further, only one occurs relatively insignificant increase in implementation.

To carry out the reaction, a solution of the aromatic compound to be hydrogenated and the ruthenium complex and an inert solvent such as benzene, toluene or xylene is mixed with the entire amount of secondary alcohol and heated with stirring. The hydrogen transfer reaction already begins at room temperature, but only produces ^{noticeable conversions from 50 0} C and undergoes a reaction maximum at about 95 ° C. The reactions are markedly reduced again above 110.degree. C. The reaction mixture is therefore preferably kept in the temperature range from 70 to 95.degree. C. with stirring. Since nitrogen has an inhibiting influence on the catalyst activity, it is advisable to carry out the reaction under a protective gas atmosphere. Noble gases or even gaseous saturated hydrocarbons can be used as protective gases.

After a reaction time of, depending on the chosen Temperature, 10 to 20 hours, the rate of reaction has dropped so far that the reaction is terminated and the reaction mixture is worked up by distillation.

The catalyst remains in the distillation residue and can be converted into ruthenium trichloride hydrate according to the methods mentioned in the literature and converted from this into the active form (J. L Levison and S. D. Robinson, J. Chem. Soc. A (1970) 2947).

example 1

To a solution of 89 g (6.5 mol) of anthracene and 29 g (0.025 mol) of H ₂ Ru (P Ph ₃ ) in 6001 ml of toluene, 5000 ml (65 mol) of isopropanol are added under an argon atmosphere and this mixture is stirred for 15 Maintained at 75 ° C for hours.

After the reaction mixture has been worked up, 41.5 g of unreacted anthracene, 48.3 g (53.1% of theory) 1,2,3,4-tetrahydroanthracene and Traces of 1,2-dihydroanthracene were obtained.

Example 2-7

45

Similar to Betspiel 1, the following approaches are implemented:

0.5 mmol of anthracene

0.025 mmol H ₂ Ru (P Ph ₃ J ₄ so

25 mmol alcohol

Benzene up to a volume of the reaction mixture of 17.5 ml

The following yields of tetrahydronanthracene are obtained from the various alcohols:

eo

Methanol 0.0% Ethanol 0.0% Isopropanol 32.7% Isobutanol 39.2% Isoheptanol 36.6% 1-phenylethanol 59.70 / 0

Claims (5)

Hydrogen transfer from a secondary alcohol patent claims: get on anthracene or anthracene derivatives using H2 Ru (P Ph3J4 or H4 Ru (P Ph3J3 as 1. Process for regiospecific Partialhydrie- catalyst selectively the corresponding terminal taring of anthracene or its derivatives, from which 5 trahydroverbindungen arise. characterized by the fact that the hydrogen transfer of secondary alcohols Thracene or anthracene derivative with a secondary pick up on aromatics is known from DE 30 13 066 C 2, Ren alcohol as a hydrogen donor in the presence, however, carbon components are completely one unspecifically hydrogenated in an inert organic solvent dissolved hydridoruthenium complex of the general io Also known is the use of ruthenium NEN formula umphosphanhydride complexes for transfer hydrogenation of olefins (T. Nishiguchi et al, j. CataL 41 (1976) 249) H _x Ru (P Ph ₃ ), or aldehydes or ketones (H. Imai et aL, J. Org. Chem. 41 (1976) 665). The use of this is new as a catalyst, where x = 2 and y = A or x = 4 and 15 catalyst type in the hydrogen transfer y = 3 is, in an amount of about 2 to 10 mol%, polynuclear aromatic compounds in the presence based on the aromatic compound used, secondary alcohols as hydrogen donors, manure, at temperatures of 50 to 110 ° C. There are three surprising effects: 2. The method according to claim 1, characterized in that that the secondary alcohol is isopropyl 20 a) Not all aromatic compounds are used But panol uses hydrogenated mononuclear products such as benzene or toluene 3. The method according to claims 1 to 2, thereby also polynuclear such as naphthalene, phenanthrene, characterized in that the secondary alcohols chrysene or pyrene are inertly hydrogenated only anthracene or its derivatives are used in a 50-100 fold molar excess. 4. The method according to claims 1 to 3, characterized in 25 b) It is not a complete, but only one marked par, that the reaction in a partial hydrogenation of the corresponding aromatics. Temperature in the range of 70 to 95 ° C carries out c) The anthracene structure is region-specific to a 5. The method according to claims 1 to 4, thereby hydrogenated nem terminal ring
characterized in that one is taking the implementation Protective gas atmosphere carries out 30 This is how the hydrogen transfer according to the invention proceeds, for example with anthracene with high selectivity vity to 1,2,3,4-tetrahydronanthracene, which is then without further purification to tetrahydroanthraquinone or naphthalenedicarboxylic acid The invention relates to a method for partial, 35 can. Benz [a] -anthracene produces 8,9,10,11-tetrahregiospecific hydrogenation of anthracene or desydrobenz [a] -anthracene or 2-methylanthracene-sen derivatives. The hydrogenation of polynuclear aro- 2-methyl-6,7,8,9-tetrahydroanthracene is formed
maten that are accessible in coal tar distillation, but also in the reaction according to the invention, in coal digestion processes or in carbohydrate hydrogenation, contain aromatic compounds which have an anthracene base to form higher-quality, commercially available products, such as anthracene, benz [a] -anthracene, or have been described many times (cf. E. Clar, Polycyclic Naphthocene and derivatives of these compounds, in Hydrocarbons, Academie Press, London, 1964, Volume where an aromatic nucleus, for example with alkyl, 1, page 290 ff.). In this reaction, which is substituted with heterogeneous alkoxy or halogen groups
Catalysts such as Raney nickel, Cu-Cr oxide or a solution of a ruthenium noble metal is carried out as the catalyst, a step complex of the general formula is always carried out
by hydrogen attachment, with a large number
of parallel and subsequent reactions in the reaction mixture H _x Ru (P Ph ₃ ),
expire. It works by choosing the catalyst and the reaction conditions to take certain routes in an inert organic solvent such as benzene prefer or to accommodate subsequent reactions, either 50 or toluene used. Where x- 2 and y = 4 or however, mixtures of products always result which * = 4undy = 3. both in terms of the hydrated region and in terms of their catalytic properties the degree of hydrogenation differ and the very activity is almost equivalent. The amount of catalyst difficult to separate from each other. is about 2 to 10 mol%, based on the Albeit already such a mixture of hydrogenated aromatic compounds. a refinement of the raw materials. Hydrogen donors are aliphatic or alidic the aim is to produce defined phosphatic-aromatic secondary alcohols such as i-process substances in the most selective reaction possible targeted panol, i-butanol, i-pentanol, i-hexanol, i-octanoI, 1-Phe end products to manufacture. It was therefore the Aufga- nyl-ethanol or 1-phenyl-propanol used. To a be to find a process that is as simple as possible, with the highest possible conversion of the aromatic compound anthracene or its derivatives to target specific fertilizers, see a higher possible Place, that is, region-specific and partially hydrogenated, excess of secondary alcohol. While to be with can and in which these compounds are roughly a 5-fold molar excess of isopropanol A conversion of 15% anthracene takes place in isolated yield without great separation effort the can. 65 under the same reaction conditions at 25 times the mola die The problem is solved by a process rem isopropanol excess, a conversion of 45%, according to claims 1-5. in a 50-fold molar excess, a conversion of It has been found that a reaction is achieved by homogeneously catalyzed 51% and with a 100-fold excess